I am performing pesudo first order kinetics. In that, I have to plot a graph between ln(qe-qt) and time. SInce the last value of qt is qe, we cannot find ln for that value. How to proceed with the data then.
Also my ln(qt-qe) values are positive whereas in literature, they have shown negative value. Is this a concern?
Thanks for help!
Hello
I Will suggest you to perform non linear kinetic modelling.
But in case of linear the qe value is obtained after extrapolation of the highest value of qt. You can fine the real value of qe by plotting qt versus time and on that graph make the projection of the highest qt value of y-axis then you Will have your real qe value.
Non linear regression will be okay and justify more with statistical errors like SSE, HYBRID, RMSE etc..
Merhaba Nur-ul Ayn.
1. Since you took the last qt as the qe value, the qe-qt value is zero. In this case, you cannot show the last point on the graph. So if you took measurements at 10 different times, you can use the first 9 points.
2. Theoretically, since the qe value is reached in infinite time, the qe value will be higher than the last qt value you measured. If you find the qe value, the qe-qt value will not be zero. In this case, you can also use the last point on the plot.
3. By plotting the qt vs t nonlinear graph, you can see to which value qt converges. That value is the qe value.
4. As a pirate way (let no one hear), you can draw the pseudo-second plot and use the qe value (1/shift) there. Try a little bit below and above too this value as the qe value.
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